In general, an image forming apparatus includes a unit attaching portion to which a replenishing unit storing developer can be removably attached. Furthermore, the image forming apparatus may include a tag reader for performing wireless communication with an electronic tag via an antenna. The tag reader includes the antenna for short-range wireless communication.
For example, the antenna is a coil antenna made of a metal foil printed on a substrate in a coil-shape. The substrate is provided on the unit attaching portion. On the other hand, the electronic tag is attached on the replenishing unit. The tag reader may read information relating to color, type, and the like of the developer from the electronic tag.
In addition, there is known an auxiliary antenna that is attached to the replenishing unit for reducing resonance frequency of the electronic tag when the antenna and the electronic tag are in close proximity.